This invention relates generally to data storage systems for handling and storing data cartridges, such as optical disk or magnetic tape cartridges, and more specifically to apparatus for removing and replacing data cartridges contained in such data storage systems.
Many different types of data storage systems exist and are being used to store data cartridges at known locations and to retrieve desired data cartridges so that data may be written to or read from the data cartridges. Such data storage systems are often referred to as xe2x80x9cjuke boxxe2x80x9d data storage systems, particulary if they can accommodate a large number of individual data cartridges.
A typical juke box data storage system may include one or more different types of cartridge receiving devices for holding the various data cartridges. For example, one type of cartridge receiving device may comprise a cartridge storage rack or xe2x80x9cmagazinexe2x80x9d while another type of cartridge receiving device may comprise a cartridge read/write device. The cartridge storage racks or magazines serve to provide storage locations for the data cartridges and are commonly arranged so that they form one or more vertical stacks, although other configurations are possible. The cartridge read/write device may be located at any convenient location within the data storage system. The data storage system may also be provided with a cartridge handling system for transporting the data cartridges between the various cartridge receiving devices, e.g., between the cartridge storage racks and the cartridge read/write devices. A typical cartridge handling system may include a cartridge engaging assembly or xe2x80x9cpickerxe2x80x9d for engaging the various data cartridges contained in the cartridge receiving devices, as well as a positioning device for moving the cartridge engaging assembly among the various cartridge receiving devices.
Data storage systems of the type described above are usually connected to a host computer system (not shown) which may access or store data on the data cartridges. For example, if the host computer system issues a request for data contained on a particular data cartridge, a control system associated with the data storage system actuates the positioning system to move the cartridge engaging assembly or xe2x80x9cpickerxe2x80x9d along the cartridge storage racks until the cartridge engaging assembly is positioned adjacent the desired data cartridge. The cartridge engaging assembly may then remove the data cartridge from the cartridge storage rack and carry it to the cartridge read/write device. Once properly positioned adjacent the cartridge read/write device, the cartridge engaging assembly may insert the selected data cartridge into the cartridge read/write device so that the host computer may thereafter read data from or write data to the data cartridge. After the read/write operation is complete, the cartridge engaging assembly may remove the data cartridge from the cartridge read/write device and return it to the appropriate location in the cartridge storage rack.
It is often necessary or desirable for a system operator to periodically access one or more of the data cartridges contained within such a data storage system. For example, it may be necessary for the system operator to remove certain of the data cartridges from time to time if they become filled with data that is to be archived at another location. The system operator may then replace the filled data cartridges with blank data cartridges. In another situation, the system operator may desire to remove one or more of the data cartridges and replace it or them with a substitute data cartridge or cartridges containing different data.
In order to accommodate the foregoing necessities, many data storage systems are provided with an access panel to allow the system operator to access to the data cartridges stored within the data storage system. While such xe2x80x9cpanelxe2x80x9d type of cartridge exchange systems are usually effective from a functional standpoint, they are usually difficult and cumbersome to implement in practice. For example, since the access panel needs to be removed in order to access the data cartridges, the data storage system must be temporarily shut-down in order to prevent the cartridge handling system from interfering with the system operator""s access to the cartridges and to prevent injury to the system operator should the cartridge engaging assembly move while the system operator""s hand is inside the data storage system. Another problem is that it is often difficult for the system operator to locate the particular data cartridges that are to be replaced. Still another disadvantage is that once the access panel has been replaced, it is necessary for the data storage system to re-inventory the data storage cartridges contained therein. Such re-inventory processes are time consuming and difficult to justify, particularly if only one cartridge has been replaced. Nevertheless, the data storage system must re-inventory the data cartridges before the data storage system can be returned to service.
Partly in an effort to solve some of the problems associated with the foregoing panel type of data cartridge exchange system, data storage systems have been developed that utilize a xe2x80x9cmail slotxe2x80x9d to allow a system operator to access the data cartridges stored in the data storage system. Such a mail slot system is useful in that it allows a system operator to access a data cartridge without the need to remove a separate access panel on the data storage system. Consequently, most mail slot type of data cartridge exchange systems eliminate the need to temporarily suspend the operation of the data storage system while the system operator is accessing the data cartridges. Unfortunately, however, most mail slot systems utilize a separate transport mechanism to present the desired data cartridge to the system operator. The separate transport mechanism increases the number of mechanical components and systems associated with the data storage system, thereby adding to the overall cost and complexity of the data storage system. The separate transport mechanism also takes up valuable space within the data storage system which might otherwise be used for the storage of additional data cartridges.
Another disadvantage associated with most currently available mail slot data cartridge exchange systems is that they can only handle one data cartridge at a time, therefore making it difficult and time consuming to replace or exchange more than one data cartridge. While mail slot data cartridge exchange systems do exist that allow a system operator to access more than one data cartridge at a time, they typically involve relatively large transport mechanisms which require a substantial amount of space within the data storage system, space which, again, may otherwise be used for the storage of additional data cartridges.
A mail slot data cartridge exchange system for a data storage system may comprise a drawer mounted to the data storage system so that the drawer can be moved between a retracted position and an extended position. A cartridge magazine for holding at least one data cartridge is sized to be removably received by the drawer so that at least a portion of the cartridge magazine is exposed when the drawer is in the extended position. A drawer stop index member is operatively associated with the drawer so that the movement of the drawer stop index member corresponds to movement of the drawer. A lock apparatus mounted to the data storage system is switchable between a locked state and an unlocked state. The lock apparatus engages the drawer stop index member when the lock apparatus is in the locked state and when the drawer is in a regulated extended position.
In another embodiment, a mail slot data cartridge exchange system is provided that comprises a drawer sized to receive at least one data cartridge, the drawer being mounted to the data storage system so that the drawer can be moved between a retracted position and an extended position. A drawer stop index member is operatively associated with the drawer so that movement of the drawer stop index member corresponds to movement of the drawer. A lock apparatus mounted to the data storage system is switchable between a locked state and an unlocked state. The lock apparatus engages the drawer stop index member when the lock apparatus is in the locked state and when the drawer is in a regulated extended position.
Also disclosed is a method for accessing at least one data cartridge contained in a data storage system that comprises the steps of providing the data storage system with a drawer sized to receive at least one data cartridge, the drawer being moveable between a retracted position and a plurality of extended positions; providing a drawer extension regulator apparatus for allowing the drawer to be extended to a selected of the plurality of extended positions; extending the drawer from the retracted position; actuating the drawer extension regulator apparatus to stop the extension of the drawer when the drawer has been extended to a selected one of the plurality of extended positions; and returning the drawer to the retracted position without further actuating the drawer extension regulator apparatus.